Coating apparatus may be used to apply a layer of primer on a substrate (such as paper) prior to the deposition of ink on the substrate. The primer may improve the fixing of the ink to the substrate and thereby improve the quality of printed text and/or images on the substrate. Coating apparatus may also be used to apply a layer of post-treatment coating on a substrate after the deposition of ink on the substrate. However, such coating apparatus may be unable to apply a coating to substrates having differing dimensions. Additionally, such coating apparatus may apply a relatively thick layer of coating to the substrate that may increase the cost of operation of the coating apparatus and may result in a relatively long drying time for the coating on the substrate.